oil/temperature warning buzzer

[Richard Woodard]

I have a 115 hp mercury outboard and the warning buzzer is going off even when it is just sitting in the garage and cold and not running all you have to do is turn on the key and off it goes.. Whats up with this?

 

[Silvertip]

Re: oil/temperature warning buzzer

Disconnect the tan wire at the bullet connector that comes from the temp sensor on the engine. If the alarm quits, the sensor is bad or the tan wire is shorted to ground. If it continues to sound off, the module is probably bad.

 

[Richard Woodard]

Re: oil/temperature warning buzzer

thanks, but the only thing I've tried that worked was disconnect from the oil level switch and I have replaced that sensor but that still does not silence the buzzer unless I disconnect the oil level sensor. Pretty frustrating to say the least.

 

[zzzzz]

Re: oil/temperature warning buzzer

is it a solid alarm or intermittent ?...the switch you replaced-is it the one in the bottom of the oil tank ?

 

[Richard Woodard]

Re: oil/temperature warning buzzer

it is a solid alarm and yes it was the one in the bottom of the oil tank.. thanks

 

[zzzzz]

Re: oil/temperature warning buzzer

Richard- it's probably a bad oil tank...the tank has built in magnets that work in conjunction with the switch and after a few years of exposure to I guess the oil fumes(??)the glue holding the magnets in place lets loose - very common with Merc oil tanks...we stock quite a few different Merc oil tanks

 

[j_martin]

Re: oil/temperature warning buzzer

What are you calling the oil level sensor?.

The level sensor is in the oil tank, in the cap assembly on mine, but it could be different. The rectangular block with several wires coming out of it is the oil warning module. If you have a solid tone and you have to disconnect that module to kill it, it's the module that's bad. Any switch or motion sensor problem should give an intermittent beep. If it's intermittent and you disconnect the tank wires to stop it, it's the tank switch that's bad. The motion sensor doesn't come into play until the engine is turning as it watches for spark pulses and motion detector pulses occuring at the same time. If either is missing, it'll sound, and if both are missing (engine stopped) it won't.

BTW, the tank switch is looking for plumb full. Anything less is supposed to set it off.

hope it helps
John

 

[Richard Woodard]

Re: oil/temperature warning buzzer

you may be right... I think I will take the tank loose and drain the oil.. then tip the tank over to see if the buzzer stops... that should let me know if it is the tank or not.. don't you think?

 

[zzzzz]

Re: oil/temperature warning buzzer

I think that would only work when the tank is good...best to let your dealer diagnose it

 

[CharlieB]

Re: oil/temperature warning buzzer

Inside the oil tank on a 4 cyl 115 uses a float in the lower 1/4 of the tank. This float has a magnetic washer epoxied the botoom, when the epoxy fails the magnet drops over the 'magnetic switch' and the alarm sounds continously.

You already confirmed this when you unplugged the bllue wire to the switch and the alarm stopped, however, replacing the switch did NOT cure the problem cause it is INSIDE the SEALED tank.

Order the replacement tank.

 

[Richard Woodard]

Re: oil/temperature warning buzzer

Thanks for everyones help. I replaced the tank and that stopped the warning buzzer...

 

[tooner]

Re: oil/temperature warning buzzer

I am so glad I found this thread!!! I had a constant alarm start on my 90Merc last weekend and was puzzled because it wasnt running hot. Turns out the sensor in my oil tank is bad. I turned the key on so the alarm would sound and disconnected the blue wire and the alarm stopped. I ordered the tank today for $69.95. If I didnt find this discussion I was going to the shop and probably would have spent about $500.00 Thanks Everyone!!!

 

[BarflyRIB]

Re: oil/temperature warning buzzer

I have the same problem - when I put the orange and blue wire from the engine together the beeps stops - replacing the sensor is no solution for me (I already tried ) - I think the magnetic float switch doesn't go up to the max when oil is in...
so the magnetic float can not be replaced? is it so that the whole tank have to be changed?
how can it get busted?

 

[CharlieB]

Re: oil/temperature warning buzzer

Barfly - This is an OLD thread.

I suggest that you start a NEW thread, include the model of your motor, then describe the symptoms and what you have tried already. Many of us will read your posting and suggest what steps you can take to determine the culprit part.